I find the foam seat too soft and that my bony ass ends up supported primarily by whatever the bottom of the seat is made of. This isn't terrible, but it isn't great. I weigh about 80kb/175lbs, for whatever that's worth.
I also find that the curve on the back protrudes too far forward at the lower back. If I spend a couple hours in the chair, my back inevitably ends up sore. This is the major problem I have with the chair.
I will say that the chair is sound without the arm rests, so if you aren't an arm rest person (I'm not) you don't need to attach them.
As with many things in life YMMV. Unfortunately, this is a hard one to try out long enough without buying to know whether or not this chair is comfy for you.
ETA: I'm about 182cm/6'1" if anybody is curious. I'm mostly tall in the legs.